title: Bone suppressed images improve radiologists' detection performance for pulmonary nodules in chest radiographs.
abstract: OBJECTIVE
  To assess the effect of bone suppression imaging on observer performance in detecting lung nodules in chest radiographs.
  
  
  METHODS
  Posteroanterior (PA) and lateral digital chest radiographs of 111 (average age 65) patients with a CT proven solitary nodule (median diameter 15 mm), and 189 (average age 63) controls were read by 5 radiologists and 3 residents. Conspicuity of nodules on the radiographs was classified in obvious (n = 32), moderate (n = 32), subtle (n = 29) and very subtle (n = 18). Observers read the PA and lateral chest radiographs without and with an additional PA bone suppressed image (BSI) (ClearRead Bone Suppression 2.4, Riverain Technologies, Ohio) within one reading session. Multi reader multi case (MRMC) receiver operating characteristics (ROC) were used for statistical analysis.
  
  
  RESULTS
  ROC analysis showed improved detection with use of BSI compared to chest radiographs alone (AUC = 0.883 versus 0.855; p = 0.004). Performance also increased at high specificities exceeding 80% (pAUC = 0.136 versus 0.124; p = 0.0007). Operating at a specificity of 90%, sensitivity increased with BSI from 66% to 71% (p = 0.0004). Increase of detection performance was highest for nodules with moderate and subtle conspicuity (p = 0.02; p = 0.03).
  
  
  CONCLUSIONS
  Bone suppressed images improve radiologists' detection performance for pulmonary nodules, especially for those of moderate and subtle conspicuity.
authors.affiliation: Radboud University Nijmegen Medical Centre, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands. Electronic address: steven.schalekamp@gmail.com.
authors.forename: Steven
authors.initials: S
authors.lastname: Schalekamp
authors.forename: Bram
authors.initials: B
authors.lastname: van Ginneken
authors.forename: Louis
authors.initials: L
authors.lastname: Meiss
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Peters-Bax
authors.forename: Lorentz G B A
authors.initials: LG
authors.lastname: Quekel
authors.forename: Miranda M
authors.initials: MM
authors.lastname: Snoeren
authors.forename: Audrey M
authors.initials: AM
authors.lastname: Tiehuis
authors.forename: Rianne
authors.initials: R
authors.lastname: Wittenberg
authors.forename: Nico
authors.initials: N
authors.lastname: Karssemeijer
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Schaefer-Prokop
mesh_terms: D000368:Aged; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013902:Radiography, Thoracic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D013382:Subtraction Technique
keywords: Area under curve; Diagnosis, computer-assisted; Lung/radiography; Radiography, thoracic/methods; Solitary pulmonary nodule/diagnosis; Solitary pulmonary nodule/radiography